Houston Methodist Hospital told ABC13 they are having to treat patients in hallways and waiting rooms.
Meanwhile, Harris Health System said LBJ Hospital has been operating under an 'internal disaster' code on an on-and-off basis since Sunday.
READ ALSO: Houston Methodist ER running at full capacity amid COVID surge: 'Highest I've ever seen'
The code means its emergency department is so saturated with acutely ill patients that ambulances are being diverted.
"We're looking at a much more serious situation, even compared to last year, and last year was devastating for so many people and so many hospitals," said Matthew Schlueter, the chief nursing officer of ambulatory care with the Harris Health System. "We are way over our comfortable capacity."
Schlueter said with nearly no bed availability, it's a high-pressure situation.
"Right now, if you're not on death's door with the most critical situation ... very high likelihood you'll have to wait in our waiting room," he said.
Plus, Schlueter said wait times are soaring.
"To get a bed, it could be up to 24 hours right now," he said.
LBJ Hospital was even forced to turn away an 11-month-old baby who needed pediatric ICU care.
"We actually initiated a transfer request to a facility with a higher level of care for pediatric patients, and we were unable to identify a facility in Houston," said Patricia Darnauer, the administrator and executive vice president for Harris Health System.
The closest available bed for a child was in Temple, Texas, which is about 150 miles away from Houston.
READ MORE: 11-month-old with COVID sent to hospital 150 miles away due to lack of bed space in Houston
Meanwhile, the delta variant surge is taking Houston hospitals by storm, where many like Ben Taub Hospital and LBJ Hospital were already facing nurse shortages.
"We are at least 100 positions short in our system to help cover the need right now," said Schlueter.
On top of the shortages, the medical staff, who have endured an immense amount of work in the last 18 months, said they are incredibly stressed and incredibly tired.
"You just don't stop," said Rene Fenner, a nurse at LBJ Hospital. "You don't stop at all. Between being completely exhausted and feeling defeated that we're dealing with the same thing that we've been dealing with and thought we got rid of. This is going to ruin healthcare. We just can't sustain this."
Harris Health System said its COVID-19 admissions are growing exponentially and are largely the unvaccinated population.
"This pushes us to the limits that we can absolutely manage," said Fenner.
Medical experts across Houston are begging people to help ease this surge by getting vaccinated and wearing a mask.
For updates on this report, follow ABC13 reporter Shelley Childers on Facebook, Twitter and Instagram.